Department of Bioagricultural Sciences and Pest Management , Colorado State University , 1177 Campus Delivery , Fort Collins , Colorado 80523 , United States.
J Agric Food Chem. 2019 Feb 20;67(7):2061-2065. doi: 10.1021/acs.jafc.8b05672. Epub 2019 Feb 11.
Glyphosate is a widely used herbicide in commercial crop production for both conventional and herbicide-resistant crops. Herbicide-resistant crops, like glyphosate-resistant sugar beet, are often exposed to multiple applications of glyphosate during the growing season. The fate of this herbicide in resistant crops has not been publicly documented. We investigated the fate of glyphosate and main metabolite aminomethylphosphonic acid in glyphosate-resistant sugar beet grown in northern Colorado. Glyphosate residues were measured via directed ultra-high-performance liquid chromatography tandem mass spectrometry analysis of sugar beet shoots and roots throughout the growing season, from samples collected at various steps during sugar beet processing, and from flow-through samples of greenhouse-grown beets. Sugar beet rapidly absorbed glyphosate after foliar application, and subsequently translocated the herbicide to its roots, with between 2 and 3 μg/g fresh weight measured in both tissue types within 1 week of application. However, only trace amounts of glyphosate remained in either the shoots or the roots 2 weeks after application. Analysis of irrigation flow-through in pot assays confirmed that the herbicide readily exuded out of the roots. Processing of the beets removed glyphosate and herbicide levels were below the limit of detection in the crystalline sugar final product.
草甘膦是一种在商业作物生产中广泛使用的除草剂，用于常规作物和抗除草剂作物。在生长季节，抗除草剂作物（如抗草甘膦甜菜）经常多次接触草甘膦。这种除草剂在抗除草剂作物中的命运尚未公开记录。我们研究了北科罗拉多种植的抗草甘膦甜菜中草甘膦和主要代谢物氨甲基膦酸的命运。通过对生长季节中不同阶段采集的甜菜茎叶和根部样本、甜菜加工过程中的各种样本以及温室种植甜菜的流动样本进行定向超高效液相色谱-串联质谱分析，测定了草甘膦残留量。甜菜叶喷后迅速吸收草甘膦，随后将除草剂转移到根部，施药后 1 周内，两种组织类型中均检测到 2 至 3μg/g 鲜重的草甘膦。然而，施药后 2 周，无论是茎叶还是根部，草甘膦的残留量都很少。盆栽试验中灌溉水流动的分析证实，该除草剂很容易从根部渗出。甜菜加工去除了草甘膦，结晶糖最终产品中的草甘膦含量低于检测限。
